Wilwood's new Billet Aluminum Master Cylinder Fluid Reservoir provides a stylish and durable 4 ounce reservoir that is manufactured from billet aluminum. These bare reservoirs requires cap assembly & seal (Part # 330-12954). Wilwood's new Billet Aluminum Master Cylinder Fluid Reservoir provides a stylish and durable 4 ounce reservoir that is manufactured from billet aluminum. These bare reservoirs can be direct mounted to Wilwood's Compact Remote Master Cylinder body utilizing the internally threaded reservoir support with the 11/16-20 thread adapter (Part # 220-12943) or as remote mount reservoir using the mounting bracket and 3/8-24 thread -3 AN fluid connector adapter (Part # 220-12942). Bare reservoir requires cap assembly & seal (Part # 330-12954).